Tenshodo/Hanazono motor bogie dc to DCC ready conversion.

I'm working towards converting my lima Class 117 DMU by removing the original Lima 'pancake motor' and substituting one of these Tenshodo/Hanazono motor bogies. As supplied, these are DC, but can be altered fairly simply to allow DCC to be used, but it doesn't tell you how, and as I've done a couple of these before (and my layout is DCC) then I thought a quick "How-To" might be helpful to anyone contemplating doing likewise.
Firstly turn the bogie upside down and you'll see a tiny screw centrally at one end, so remove this and unclip the bottom cover to reveal the motor 'innards', the drive worms and axles/gears. You'll need to be careful as you lift out each axle, then ease up and out the motor itself, and magnet, so you're left with an empty casing. At each side of the motor casing you can see the sprung metal wheel pickups have a central folded over metal tab which goes inside the motor case, contacting the motors brush holders internally. These tabs need to be folded out of the case interior, and back down the outside of the motor casing, thus disconnecting the power from the pickups to the motor brush holders, since with DCC you need to completely isolate both sides of the motor supply from the input voltage. In this pic, you can see the metal pickup tags have been removed from the motor interior ready to be folded back down the outside on assembly.

 

Now the real fun starts, as it's time to start reassembling the bogie! Slide the motor complete back into place, ensuring that the two copper tags attached to the brush holders pass straight through the casing, then with that in place, refit the two wheelsets, making sure that the sprung parts of the pickups seat correctly behind each wheel as you replace them. These bogies come with 3 different metal brackets which can be used to attach any bogie sideframes to the bogie itself, and I intend to re-use the bogie sides from the redundant original Lima bogie. The chosen bracket is held in place by the bottom cover, the small locating spigot of which can be seen in the first pic, so you have something of a balancing act trying to keep the wheelsets located, bracket in place and refit the bottom cover, all the while hoping not to disturb the pickups behind each wheel! Once you've achieved that and the bottom cover is clipped into place, all that remains is to refit the tiny screw. You can then see that you now have 4 terminals where once there were two, the copper ones are the direct motor connections, the metal tabs are the supply pickups from the rails. Here we are partly reassembled.

 

Hopefully in this pic, you can see the 2 metal tags, one each side, being supply voltage from the rails. The two copper tags above the motor are the motors direct connections, so to wire in a DCC decoder, all that's needed is Red and Black of the decoder connected to the metal pickup tags (right hand side in direction of travel is normally the Red), Orange and Grey from decoder go to the motors copper tags, again right side in direction of travel (this is marked on the motors bottom cover) should normally be the Orange connection. You can see the bracket for bogie sideframe attachment, one each side, (with the hole in) in this pic, metal tags may need to be adjusted to clear any obstructions, copper motor connections will need to clear any swivelling parts also. Unfortunately the pic isn't perfectly focused (phone camera!), but hopefully you get the idea.
Keith.

 

Hi Andrew.
As far as I'm aware, the diameter given is usually that of the part that sits on the rails. There are several suppliers of these Tenshodo bogies but most had no stock of the size I needed, I eventually found 'Scalelink' had decent stocks and a very fast delivery (ordered Sunday, with me the following Tuesday by 1st class post), they're not cheap at £45 but if it's what you need then not much choice. Can I ask, have you had a look at the 'Peters Spares' website as He specialises in Hornby spares and you just might get a complete replacement of the genuine part for your Class 110, alternatively He might be able to suggest a later bogie that may fit. I say this because a year or two ago, I rebuilt an elderly Triang 2Bil 2 car EMU using a Hornby Class 90 motor bogie with a decent can motor and none of the 'serrated' Triang wheels! As a bonus, a Hornby replacement just might be cheaper than the Tenshodo and possibly fit without much modification. Don't forget that you also need to measure the wheel centres if you're going for a Tenshodo bogie.
Keith.

 

Hi Bob.
It's been a while since I did this conversion, and I've moved into 0 gauge since then, but I'm happy to help if I can. The easiest option is to cut and extend as you say, matching the wheelbase. I only converted one motor bogie, but obviously the unit would be more powerful with two, and no, you're not mad to attempt this, it ought to be a fairly simple job overall, though if you are fitting the bogies opposite ended to one another, you will of course need to make sure that when the leading bogie is in forward mode, the rear one will need to be in reverse mode, so motor connections will need to be opposite on the rear bogie. I built a model of Bulleid's "Leader" loco a while back which used one of the Hanazono motors built into the bogie, and opted for two motors, one in each bogie, resulting in quite a powerful loco. This used two decoders which I programmed identically, thus not needing a 'consist' but again, the motors were connected opposite to one another so that both drove in the same direction. If you use identical decoders (or possibly one decoder with enough current handling capacity for both motors stall current) then I doubt it should be a problem.
Keith.